In her editorial (cross-posted below), Lewis explains why she has “opted out” of the “weight-loss game.” She confides that she has been “fat” since she was a child. She still remembers the humiliations, which continue to this day– especially when she visits a primary care doctor.

It doesn’t matter whether she is seeing the physician because she has broken an ankle or needs contraception. Inevitably, he or she brings up her Body Mass Index (BMI.) And when a GP admonishes her that she should diet and work out, he rarely asks what she eats now, or how much she exercises. He doesn’t listen; he lectures.

In fact, Lewis does care about her health: she exercises regularly and has switched to a whole meal vegetarian diet. For years, she has been in good health. But her BMI remains above 30.

What Many Doctors Don’t Know—And What Even the Experts Don’t Understand

What these general practitioners don’t know is what doctors and scientists who specialize in obesity have discovered: the vast majority of overweight patients cannot shed pounds—and keep them off—even in highly controlled experimental settings where patients diet and exercise under a doctor’s supervision. As I explain in the post below two years after starting a diet, roughly 95% will have put all of the weight back on.

And even the experts who study the obesity epidemicdon’t understand why.

What about folks who combine intensive lifestyle changes with drugs designed to help us lose weight? “Studies show that patients on drug therapy lose around 10 percent of their excess weight,” but “the weight loss plateaus after six to eight months,” UCSF’s Medical Center reports. “As patients stop taking the medication, weight gain usually occurs.”

They suggest that chronic overeating represents asymptomrather than the primary cause of piling on the pounds. Indeed, Ludwig and Friedman argue, dieting itself may induce changes in our metabolism that leads us to regain weight when we begin to lose it.

Ludwig and Friedman compare the process to what happens when patients suffer from “edema, a common medical condition in which fluid leaks from blood vessels into surrounding tissues. No matter how much water they drink, people with edema may experience unquenchable thirst because the fluid doesn’t stay in the blood, where it’s needed.

At first blush, this sounds like progress: Enlightened employers are doing their best to encourage employees to take care of themselves. There is just one catch: we have no hard evidence that these programs either improve health or lower health care bills.

RAND had collected information about wellness programs from about 600 businesses with at least 50 employees and analyzed medical claims collected by the Care Continuum Alliance, a trade association for the health and wellness industry.